The Schiller figure he references might include all publicly traded companies. If so, it might suggest that less well-known companies (outside the 500 most popular) are over-priced. But since the 500 most popular drive the market, you can't conclude a crash from that.
Most large-cap companies I have been looking at are trading at 15 year lows for the P/E, and at close to 15 year highs for dividend ratios. They still might be over-priced in an absolute sense, but we haven't seen prices this good in 15 years.